buildozer does not sort external dependencies in deps

[peakschris]

Given this input:

deps = [
    "@b",
    "@a",
    "//src/b",
    "//src/a",
],

Buildozer will generate:

deps = [
    "//src/a",
    "//src/b",
    "@b",
    "@a",
],

is there a reason that the external dependencies are not sorted? This is in a cc_test rule.